It looks like Peter Todd maliciously published information about a bug/exploit that had just been fixed in BU.
Very possible.
Now that BU is gaining serious momentum, Core is pulling out all the stops and resorting to dirty tricks. They are terrified of losing control.
When Mike Hern rage-quit Bitcoin development a while ago, there was real momentum to raise the max block size, and get away from what the Blockstream core devs wanted -- the roundtable consensus agreement (or whatever it was called) was designed to pour cold water on that movement. However with it being very clear that blockstream and their core devs had no intentions of following through on their obligations to that agreement, the miners now do not trust the blockstream core devs anymore, and are moving to alternate implementations. It seems that blockstream is trying other tactics to pour cold water on this movement too.